Automatic control for electric circuits



April M, 1944. R F. STEWART ET AL 9 9 AUTOMATIC CONTROL FOR ELECTRIC CIRCUITS Filed Jan. 22, 1942 3 Sheets-Sheet l llllalllvku 0367 2.27 Steward;

fauZ Wli'lrod INVEATTORS amyzmw ATTIZI R N EYI April H, 1944 F2. sTEWART ET AL AUTOMATIC CONTROL FOR ELECTRIC CIRCUITS Filed Jan. 22, 1942 3 Sheets-Sheet 2 April 1944- RF. STEWART ET AL ,3

AUTOMATIC CONTROL FOR ELECTRIC CIRCUITS Filed Jan. 22, 1942 3 Sheets-Sheet 3 flberiffliewr 47' fazzZ Wl'lrod,

INVENTORS Patented Apr. 11, 1944 UNITED STATES i ATENT OFFICE AUTOMATIC CONTROL FOR ELECTRIC CIRCUITS Robert F. Stewart and Paul W. Elrod, Franklin, Ohio; said Elrod assignor to Oh-mer E. Stewart,

Middletown, Ohio 4 Claims.

This invention relates to automatic control for electric circuits and has for an object to provide apparatus of this character for controlling the predetermined timing for electrical devices, such as heating, timing, signaling, lighting devices Without the use of tapes or ribbons. I

An important field of application of the invention is in the remote control and program selection in the operation of radio receivers and this embodiment of the invention is chosen to illustrate the construction and operation.

A further object is to provide apparatus of this character which will be formed of a few strong, simple and durable parts, which will be inexpensive to manufacture, and which will not easily get out of order.

With the above and other objects in view the invention consists of certain novel details of construction and combinations of parts hereinafter fully described and claimed, it being understood that various modifications may be resorted to within the scope of the appended claims without departing from the spirit or sacrificing any of the advantages of the invention.

In the accompanying drawings forming a part of this specification:

Figure 1 is a front elevation of a clock equipped with time selector disks and coacting switch mechanism corresponding to four radio broadcasting stations from which programs are desired to be heard at preselected times.

Figure 2 is a vertical sectional view taken on the line 2-2 of Figure 1 with parts in elevation.

Figure 3 is a fragmentary horizontal'sectional view taken on the line 3-3 of Figure 2.

Figure 4 is a detail sectional view taken approximately on the line 4-4 of Figure 2.

Figure 5 is atop plan view of the time controlled switch for controlling the power circuit and the tuning push buttons of a conventional push button control radio receiving set.

Figure 6 is a detail sectional view, with parts in elevation, of the switch shown in Figure 5.

Figures '7, 8, 9 and 10 are diagrammatic views showing different portions of the circuit controlling switch contacts of the switch shown in Figure 5.

Figure 11 is a wiring diagram showing the electrical connections of the various parts of the apparatus.

Referring now to the drawings in which like characters of reference designate similar parts in the various views, l0 designates a clock which is mounted in a casing H having a plurality of verdisks 1%, that is forty-eight contacts.

tical slots l2 in the front wall below the clock separated by partitions 13. A shaft !4, see Figure 2, is journaled in the end walls of the clock casing and is provided with a plurality of disks #5 loose thereon disposed in the slots, each having a projection i6 by means of which the disk may be rotated on the shaft. All of the disks are time selector disks for desired programs and each disk corresponds to a fifteen minute time period, and the time corresponding to each disk is designated by quarter hour division marks I! on the clock casing, the hour division marks being designated by numerals 18 corresponding to the hours from one to twelve. There are forty-eight disks.

Back of the disks l5 a bar I 9 of insulating material is disposed on the bottom of the clock casing and is provided with an arcuate front wall 29 into which is recessed a plurality of switch contact bars 2| or arcuate cross section, these bars extending longitudinally across all of the disks and corresponding to respective radio broadcasting stations, the identifying letters of.

which are marked on the clock casing in a vertical row at each end of the series of disks as indicated at 22 in Figure 1. In the present embodiment of the invention there are four broadcasting stations denoted by four respective bars 2!.

Each disk is provided with a radially disposed spring pressed contact 23 adapted to be lodged on a respective bar when the disk is manually turned to select a broadcasting station. Each disk, which is formed of insulating material, is provided with an arcuate conductor 24 which is in electrical contact with the respective radial spring pressed contact 23 and is countersunk in the periphery of the respective disk. A spring pressed brush 25 is disposed obliquely in the bar l9 above each disk and has wiping engagement with the conductor 24 of the respective disk. The disks, bars, the contacts and the brushes constitute a station selector switch which may be manually closed by manipulation of the disks to select a desired station.

The time selector for the programs comprises a series of switch contacts 26 arranged concentric with the hour and minute hand arbors which are extended through the back of the clock, the segments being carried on the back face of a disk 2"! of insulating material of which is secured to the back of the clock in any preferred manner. Each one of these contacts corresponds to a quarter hour time period so that the corn tacts are equivalent in number to the number of In the wiring diagram shown by Figure 11 the clock dial is shown diagrammatically and the markings on the dial are arranged to correspond to respective contacts 25.

A movable switch arm 25 is secured to the hour hand arbor and has wiping contact with the switch contacts 26, making one revoiution every twelve hours. The switch arm is insulated from the arbor as shown at 29 in Figure 2 and is provided with a brush 35! which has wiping engagement with a conductor ring 3i which is mounted on the disk 21. Each one of the switch contacts 26 is connected by a circuit wire 32'tc the brush 25 of a respective station selector disk 55. A conductor wire 33 connects the conductor ring 3! with a time controlled switch indicated at -34 in Figure 11 and shown in detail in Figures to inclusive.

The switch 3 may be called a power control switch and comprises a block 35 of insulation on which three leaf spring switch contacts 36, 3?, 3? are secured at one end. The rotary member of the switch comprises a drum 9 having four transverse equally spaced teeth 35 upon which is free ends of the contacts 36 ride and then drop off during rotation of the drum to form circuit closers. The drum 9, see Figure 2, is formed of insulating material and is mounted on the minute hand arbor of the clock. The drum makes one revolution per hour so that the four teeth represent fifteen minute intervals of the hour and form circuit controllers each fifteen minutes of every hour.

It will be pointed out that the leaf spring switch contacts 36, 31 and 38 are of respectively difierent lengths, the contact 35 being shortest, the intermediate contact 3'! being greater in length than the contact 38, and the contact 38 being longer in length than the intermediate contact. A hook shaped conductor 4!! is secured to the short contact 35 and overlies the intermediate contact 37. A hook shaped conductor 41 is connected to the intermediate contact 3'! and overlies the long' contact 38. When the short contact drops oi? of a tooth the conductor 4% thereof will. bridge the short contact and the intermediate contact and form a circuit controller until the intermediate contact drops off the same tooth during rotation of the drum. When the intermediate contact drops off the tooththe conductor 4| will bridge the intermediate contact and the long contact 38 and form a circuit controller until the long contact drops off of the tooth.

The short contact 36 of the switch 34 is-connected. by conductor wire 42 to a solenoid t3 the core it of which is secured to a bar 65 on the receiving set upon which bar the radio tuning push buttons 46 are located. Also this bar carries the movable arm 41 of a power switch which will be closed by contact of the arm with a fixed contact 48 in a circuit 59 of the radio to turn on the radio.

The intermediate spring switch contact 3'! is connected by a conductor wire 56 to a step down transformer or low voltage transformer 5i which is operated from the service line 52. The other end of the transformer is connected by a conductor wire 53 to the other end of the solenoid 43.

A conductor wire 5 is connected to the wire 53 and is connected to one end of respective solenoids ii for the push buttons 26 of the receiving set. The other ends of the solenoids are connected respectively by wires 55 to respective switch contact bars 21 corresponding to the broadcasting stations. There are four of the solenoids 47 in the present embodiment.

The operation of the switch 3a is only momentary and takes place at fifteen minutes time intervals. First the short spring switch contact 38 will drop down oii one of the teeth 39 of the drum and its bridging conductor 49 will engage the intermediate contact 31 thereby energizing the solenoid 43 through the solenoid circuit which may be" traced as the wire 5%, wire 53, and wire 42. When the solenoid is energized the core it is drawn into it and the bar at is moved out to open the radio power switch and terminate a previous program if such a program be in operation. Next the intermediate leaf spring contact 40 will drop off the same tooth and thus engage its bridging conductor 4! with the long leaf springcontact 38 which later is connected to the wire 33 leading from the conductor ring 3! of the clock driven time selector disk 27. Thereupon, as" suming that one of the programs selector disks l5 has been adjusted to bring its spring pressed contact 23 onto a respective switch contact bar 2! corresponding to a desired broadcasting. station, a circuit is momentarily made for operating the respective radio tuning push button it which circuit may be traced as including the wire 33, conductor ring 3'], brush 3i], movable switch arm 28, respective contact segment 2s, respective wire 32, respective brush 25, respective spring pressed contact 23, respective bar 2!, respective wire 55, respective solenoid i? and from the solenoid through the wire 54, wire 53, transformer 5!, and wire 50. Thus said solenoid is energized to pull in its core 41' and push in a respective push button. The push button .moves the bar 35 to close the radio power switch e! and tunes in the selected program. Subsequently the long leaf spring contact 33 rides ofi the tooth and the circuit just traced is broken so that the selected program continues for fifteen minutes When again the cycle of operations takes place.

The partitions l3 between the selector disks iii are provided with ribs 57, see Figure 2. The ribs are equal in number to the number of bars 2| corresponding to the broadcasting stations and also an additional ib which denotes a neutral space on the insulating bar l9, as also shown in Figure 2. The projection 16 on any selector disk l5 when brought into alignment with a predetermined rib 51 indicates that proper registration is being made between th spring pressed contact 23 of the disk and with one of the contact bars 2| or with the neutral space.

The leaf spring contacts 36, 31 and 38 are each provided at the rear end with an open loop 53 against which a respective adjusting screw 59 abuts to adjust the contacts relatively to each other and to the teeth of the drum.

Since the operation of the parts has been described as the description of the parts progressed it is thought that the invention will be fully understood without further explanation.

What is claimed is:

1. A program selector for a radio receiver comprising, an arcuate series of conductor bars representing different radio stations, selector disks having spring pressed contacts rotatable manually to engage the bars, an arcuate conductor fixed to the periphery of each disk in permanent contact with the spring pressed contact thereon, a brush contact pressed to engage each of said arcuate conductors, a time selector dial having mounted thereon an inner circular contact ring and an outer segmental circular series of contacts, circuit wires connecting the segmental contacts with the respective brush contacts, a rotary contact disposed to maintain contact with said ring and to successively engage the segmental contacts, a power controlling switch, a circuit maker and breaker, a conductor connecting said switch to said ring, clock mechanism for operating the rotary contact, the switch and the circuit maker and breaker, a source of electricity, solenoids operative to control a radio receiver and to open and close the switch, and conductors connected to the source of electricity, the solenoids, the circuit maker and breaker, and conductor bars, the arrangement being such that the circuit maker and breaker first operates to energize the switch solenoid to open the switch and terminate a program then energize a tuning button solenoid to tune in a predetermined program determined by the setting of a respective selector disk and simultaneously close the switch of the receiver to commence the selected program.

2. The structure as of claim 1 and in which the circuit maker and breaker comprises an insulating block, leaf spring contacts secured at one end to said block and respectively increasing in length, a clock actuated drum making one revolution each hour and provided with longitudinal teeth at spaced intervals corresponding to the moment of changing from one program to another,

said teeth being preferably four in number and representing fifteen minute time periods, said leaf spring contacts preferably being three in number, a hook like conductor carried by the shortest contact adapted to bridge the intermediate contact when the short contact rides off one of the teeth of the drum, and a hook like conductor carried by the intermediate length leaf spring contact adapted to bridge the longest leaf spring contact when the intermediate length contact rides off of said tooth, the leaf spring contacts when bridged by the conductors forming circuit closers, the leaf spring contacts riding off of said rib at successive short time periods to open circuit position, the arrangement being such that the closed circuit position of the leaf spring contacts is only momentary to cause an impulse from a source of electricity to the various solenoids for terminating one program and commencing a new program.

3. The structure as of claim 1 and in which the selector disks and the segmental circular se ries of contacts are each forty-eight in number to represent fifteen minute time periods throughout a twelve hour broadcasting period,

4. The structure as of claim 1 and in which the clock operated contact is connected to an insulated disk and insulated from the hour hand arbor ,of the clock.

ROBERT F. STEWART. PAUL W. ELROD. 

